1. Field of the Invention
The subject invention relates to automatic process equipment, and more particularly, to robotic work equipment.
2. Description of Related Art
Typically, in the prior art, component leads have been trimmed individually by hand or by some form of router mass lead trimmer. Hand trimming is normally used when trimming before wave solder or when no exposed lead base metal is allowed. The router method involves using a mass lead trimmer to trim leads after wave solder.
It has recently appeared desirable to trim leads to within 0.254 mm (0.010 inch) above the surface of printed wiring boards (PWBs), for example, in order to enable the packing of circuit cards closer together in confined areas such as in submarines. Mass lead trimming used after wave solder is fast, but the large blade required cannot adjust for the inherent warp in every PWB. As a result, PWBs can be severely damaged when trimming to tolerances as tight as 0.254 mm (0.010 inch).
Hand trimming to achieve tight tolerances is slow and laborious, often taking more than 30 minutes to trim a board. It also suffers from lack of uniformity, inability to trim hard leads, and the likelihood of fracturing solder joints if trimming is performed after solder.
Thus, there has been a need in the prior art to flexibly automate lead trimming operations in order to achieve tight trim tolerances and increase quality. It would be highly desirable not only to be able to trim to within 0.254 mm (0.010 inch) of the PWB surface, but also to trim to the contour or warpage of the board.